Gardaí say they detected 459 instances of suspected drink-driving over the Bank Holiday weekend.
Assistant Garda Commissioner Eddie Rock said that while the number of road deaths was down compared to other Bank Holiday periods, safety messages were not getting through to many drivers.
Speaking on RTÉ Radio's Morning Ireland, he said there was a hardcore of drivers who continued to ignore warnings.
He also said that arrests for drink-driving took place mainly around the same times that most fatal road accidents occur.
31 people have died on the country's roads so far this month.
310 people have been killed in road accidents so far this year. That is 12 fewer than in the same period last year.
